North Huajin (Liaoning) Petrochemical Co., Ltd. supplies HD5070EA as a high-density polyethylene injection-moulding grade produced at its Panjin, Liaoning polymerization complex. The resin is intended for thin-wall injection-moulded articles in which cycle-time reduction, rapid cavity filling, and consistent part weight are governing process variables. The grade designation carries a nominal melt flow rate of 7.0 g/10 min at 190 °C under 2.16 kg load and a nominal density of 0.950 g/cm³, determined respectively to ISO 1133-1:2022 and ISO 1183-1:2019. The product is a narrow-molecular-weight-distribution HDPE copolymer with a stabilization package intended for multiple heat histories in injection moulding. HD5070EA does not contain the slip or antiblock additives commonly found in blown-film HDPE grades; absence of those surface-modifying additives supports predictable weld-line strength and adhesion in moulded parts but reduces surface slip performance. The pelletized product is supplied in bulk, box, or bag configurations, with lot-specific certificates of analysis governing final part qualification. Where a delivered lot has not been accompanied by a certificate of analysis, published grade datasheet values should be treated as typical control values rather than release limits.

What Are the Certified Physical Properties of HD5070EA?

The tabulated values below reflect the manufacturer’s typical control ranges for HD5070EA. They are not maximum or minimum specifications unless a customer-specific purchasing specification states otherwise. Conversion conditions, regrind content, pigmentation, and mould cooling rate shift these values in finished parts.

The melt flow rate of 7.0 g/10 min positions HD5070EA among medium-flow injection-moulding HDPE grades. It is below the very-high-flow injection grades above 9 g/10 min, which typically contain lower molecular weight fractions and exhibit measurable reductions in tensile yield stress and environmental stress crack resistance. It is above fractional-melt HDPE grades below 1.0 g/10 min, which are preferred for blow moulding and pipe extrusion. Lot-to-lot melt flow variation is generally maintained within ±0.5 g/10 min, but certificate-of-analysis verification is required when a part standard imposes a narrow melt-flow window.

On a 350 t hydraulic injection moulding machine equipped with a 22:1 L/D general-purpose screw, 2.2:1 compression ratio, and checked-ring non-return valve, the following starting window is used for HD5070EA: feed zone 210 °C, compression zone 225 °C, metering zone 235 °C, nozzle 240 °C, mould surface temperature 25–45 °C, injection speed 80–120 mm/s, transfer to hold at screw position 6–10 mm, hold pressure 40–70 MPa, back pressure 0.3–0.8 MPa, screw rotation 80–120 rpm, and cushion 3–6 mm. The grade normally requires no predrying because HDPE has low equilibrium moisture absorption; if cold pellets are transferred into a hot, humid moulding hall above 60 % RH, surface condensation can occur. In that case, tray drying at 60–70 °C for 1–2 h in dehumidified air is adequate. Residence time above 250 °C should be kept below 6 min; sustained exposure above 280 °C for more than 10 min induces thermo-oxidative degradation, measurable as carbonyl oxygenate formation and an increase in melt flow rate. Cooling time for a 2 mm wall thickness is typically 8–18 s, scaling approximately with wall thickness squared. When short shots occur in thin-wall cavity sections, raising the metering or nozzle temperature within the allowable window is preferred over increasing boost pressure beyond 100 MPa, because the shear-thinning response of HD5070EA is weaker than that of fractional-melt HDPE. Regrind addition up to 20 wt% is commonly practised; if regrind level exceeds 30 wt%, melt flow should be rechecked to ISO 1133-1:2022 because repeated heat histories can shift the value upward by 0.5–1.0 g/10 min.

When HD5070EA Replaces a Blow-Moulding HDPE in Multi-Product Plants

Substitution of HD5070EA into blow-moulding or blown-film lines is not technically equivalent. The higher melt flow rate of HD5070EA reflects a lower weight-average molecular weight than blow-moulding HDPE grades produced on the same polymerization platform. That lower molecular weight reduces zero-shear viscosity and extensional viscosity, which lowers injection fill pressure and improves thin-wall flow. The same property also reduces parison hang strength and melt strength. A blow-moulding HDPE from the same asset family, with nominal melt flow rate below 0.5 g/10 min and density of 0.953–0.956 g/cm³, maintains a stable parison under gravity and can withstand the stretching required in extrusion blow moulding. HD5070EA, at 7.0 g/10 min, sags excessively in parison geometries and cannot sustain a uniform blow-moulded wall. In blown-film extrusion, the lower melt strength causes bubble flutter and gauge variation. The grade is therefore confined to injection moulding operations and should not be processed on extrusion blow-moulding or blown-film equipment as a drop-in replacement.

Environmental Stress Crack Resistance and Low-Temperature Impact Behaviour

The comonomer distribution in HD5070EA provides better environmental stress crack resistance than a high-density homopolymer of equivalent melt flow rate, but the moderate molecular weight limits resistance relative to blow-moulding HDPE. Published ESCR data for HD5070EA as a specific commercial configuration is limited; where a loading environment contains detergents, alcohols, hydrocarbon-based antioxidants, or polar aggressive fluids, the article should be evaluated by ISO 16770:2019 full-notch creep test rather than relying on short-term ranking tests alone. When ASTM D1693-15 Condition B is used as an incoming ranking tool, injection-moulded plaques of high-flow injection HDPE typically produce shorter failure times than compression-moulded plaques of a 0.35 g/10 min blow-moulding HDPE. This is the principal trade-off for the processing advantage of HD5070EA.

Low-temperature performance follows the same structural logic. Notched Charpy impact at -20 °C is typically 1.5–2.5 kJ/m² for this grade. The copolymer chain architecture supports freezer-crate service down to approximately -20 °C; below -30 °C, HDPE becomes brittle and continuous service in load-bearing parts should be avoided unless the part geometry is heavily radiused or a toughening modifier is introduced. For thin-wall articles, impact performance is strongly dependent on gate placement, weld-line position, and cooling-rate-induced crystallinity gradients. Slow cooling in thick sections increases crystallinity and can reduce notched impact toughness compared with rapidly cooled thin walls.

In thin-wall transport and houseware applications, HD5070EA is used for crates, tote boxes, storage bins, closures, and appliance housings with wall thickness between 0.8 mm and 3.0 mm. Multi-cavity tools with hot-runner systems utilize the grade’s high flow to fill long flow paths, but published spiral-flow data for HD5070EA in production hot-runner configurations is limited. Mould-filling simulation should therefore be validated with a pressure-drop study on the production tool rather than relying solely on laboratory spiral-flow correlation. When pigmented with carbon black at 2.0–2.5 wt% or compounded with a hindered amine light stabilizer system, the resin can be considered for outdoor crates and bins. Natural HD5070EA without UV stabilization is susceptible to photo-oxidation, surface crazing, and loss of elongation after prolonged subtropical sunlight exposure. Weld-line strength is process-dependent; gate locations should be placed so that weld lines occur in low-stress regions, because high-flow HDPE can produce lower weld-line integrity than fractional-melt HDPE under the same melt temperature.

For Outdoor Service and Oxidative Stability Limits

For outdoor service and oxidative stability limits, the natural pellet includes a primary antioxidant and secondary phosphite stabilizer but no light stabilizer. That package protects the resin during compounding and melt processing but does not prevent photo-oxidation. Extended UV exposure of natural HD5070EA increases carbonyl index, reduces elongation at break, and produces surface microcracking. For outdoor articles, a well-dispersed carbon black masterbatch at 2.0–2.5 wt% or a hindered amine light stabilizer system is required; dispersion quality should be verified by ISO 18553:2002 or an equivalent optical microscopy method. Oxidative induction time of unstabilized pressings can be measured by ISO 11357-6:2018; for HDPE formulations without additional long-term heat stabilizers, OIT at 200 °C is typically 20–40 min. Continuous service temperature in air is below the Vicat softening point; load-bearing service above 80 °C is not recommended for continuous use. HD5070EA is not intended for prolonged contact with aromatic hydrocarbons, chlorinated solvents, or strong oxidizing agents at elevated temperature. Such media can swell the polymer matrix and accelerate environmental stress cracking. For hydrocarbon fuel tanks, chemical containers, or detergent bottle service, a dedicated high-molecular-weight HDPE with demonstrated ESCR should replace HD5070EA.

Across the Storage, Handling, and Compliance Envelope

Across the storage, handling, and compliance envelope, HD5070EA is supplied as a pellet with bulk density of 0.60–0.62 g/cm³ and retained moisture content below 0.01 wt% when stored in closed silos at 25 °C and 50 % RH. Food-contact status is supported by FDA 21 CFR 177.1520(c) for olefin polymers and EU 10/2011 for plastic materials intended to come into contact with food. Total migration testing under ISO 10106:2016 should be conducted on the finished article because printing inks, adhesives, regrind streams, and processing aids can alter compliance. The product is not formulated with phthalates, bisphenol A, or heavy-metal pigments. Under REACH, monomers and additives are registered; no substance of very high concern above 0.1 wt% is declared. Pellets should be stored away from ignition sources and oxidizers. If pellets are abraded into dust, the powder may form a combustible dust concentration; a dust hazard assessment under EN ISO 80079-36:2016 is required when handling large quantities in enclosed conveying systems.